The present invention relates to the analyzing of the quality of transmitted video images, and more particularly to an in-service, realtime picture quality analysis method that does not require a broadband reference video signal at a test point.
Currently picture quality measurements are based upon a full bandwidth picture differencing method using a human vision model algorithm, such as the Sarnoff Corporation JNDmetrix.TM. algorithm. In this method a reference (original) video signal is compared against a test (impaired) video signal. This requires the full bandwidth reference and test video signals to be available at a test point in order to perform picture quality analysis.
There are two ways the reference video signal may be made available at the test point:
1. Pre-storing the reference video signal on the test system--this requires prior knowledge of reference video scenes which limits its usefulness to out-of-service and non-realtime applications; and PA1 2. Sending the reference video signal to the test point over a low bandwidth data link--this requires a dedicated data link to transport the reference video signal to the test point on demand as well as posing bandwidth limitation issues, and therefore is not useful for realtime picture quality analysis.
What is desired is a method of picture quality analysis that may be performed real time while the system under test is in-service.